Multiple position actuator



H. M. GEYER 2,801,616

MULTIPLE POSITION ACTUATOR 2 Sheets-Sheet I Aug. 6, 1957 Filed Dec. 8, 1955 Iellmlu Aug. 6, 1957 H. M. GEYER MULTIPLE POSITION AcTUAToR 2 sheets-sheet 2 Filed Dec. 8, 1955 HIS ATTORNEY MULTIPLE POSITION AcrUA'roR Howard M. Geyer, Dayton, Ohio, assignor to1G'eneral Motors CorporationpDetroit, Mich., a corporation of Delaware Application December 8, 1955, Serial No.` 551,821

Claims. (Cl. 121-40) This invention pertains to linear actuators and particularly to an actuator with a mechanical stroke limiter.

. In using linear actuators f-or moving a control surface or load, as, for example, with movable surfaces of an aircraft, it is often desirable to provide multiple positions of actuation. Various lengths of stroke are then needed in the one or more actuators utilized. Previous actuators have been operated by fluid under pressure to vary actuator position and, at best, provided lock means on a stroke shaft which cannot maintain positive relative positioning and do not provide stops for multiple position actuation.

An object of my invention is -to provide a lluid pressure operated actuator with mechanical stroke limiting means providing positive multiple positions of actuation.

Another object is to provide an actuating means having a releasable stroke limiting device with fixed multiple stroke extension positions and unrestricted retraction under any condition.

`Another object is to provide a multiple position linear actuator capable of synchronized operation with like actuators in each respective position.

The aforementioned and other objects are accomplished in the present invention in an actuator which includes a casing or cylinder divided into extend and retract chambers by a reciprocal piston. These chambers communicate with a fluid pressure source controlled by a selectively operative control valve determining iiuid flow for fully retracting or extending the actuator in a conventional manner. Also provided is a mechanical power transmitting means for operatively connecting the actuator in synchronism with like actuators as disclosed in my Patent 2,657,539 of November 3, 1953, Synchronized Power Transmitter. The actuator is capable of moving an actuating rod connected with a piston from a fully retracted to a fully extended position and vice versa. To` provide multiple position actuation, the actuator is disposed with movable stroke limiting means for mechanically permitting selective engagement of stop members, or jaws, with a stroke limiting yoke, flange, tooth or hook portion. The stop members are pivotally disposed on the casing or cylinder of the actuator which may be termed the first fluid motor. Also disposed on the casing or cylinder in operative relationship with the stop members is a second fluid motor which is operable independently of the first fluid motor.

The second fluid motor also includes a casing or cylinder having a piston reciprocally disposed therein. The piston and cylinder form a chamber which may communicate with a separate or the same fluid source as the first fluid motor or actuator itself but is necessarily provided with a separate control valve for selectively actu-` ating the piston of the second fluid motor to an extend position. A spring means provides the force for moving the piston the other way. Fluid ports are provided with the second motor connected to a pressure and drain conduit respectively. These fluid ports may also permit intcrconnection with similar second uid motors on ICC actuators synchronized mechanically in their actuator or rst uid motor portions as disclosed in my aforementioned patent. The fluid ports may be connected by suitable conduits to permit synchronized fluid actuation of similar second fluid motors disposed on like actuators.

The piston of thesecond fluid motor is selectively connected wtih a releasing means engaging the stop member. This connection permits selective engagement of the stroke limiting means for providing multiple positions of actuation. The stop members are so disposed that the stroke limiting means can selectively limit the stroke of the actuating rod to less than full extend actuation while permitting unrestricted retraction under any condition.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings wherein a preferred embodiment of the present invention is clearly shown.

In the drawings:

Figure 1 is a partially sectioned plan view of an actuator having a stroke limiting means for providing multiple positions of actuation in the present invention.

i Figure 2 is'a left end elevational View taken in section along line 2 2 of Figure 1 showing synchronizing gearing and extend fluid pressure ports of the rst tluid motor in my invention.

Figure 3 is a right end elevational view of the actuator in Figure 1 showing the extend iluid pressure ports of the rst and second fluid motors and the end view of the storke limiting means.

Figure 4 is a side elevational view of the actuator taken partially in section along line 4-4 of Figure l to show the first iiuid motor and stroke limiting means together with a schematic representation of a source of iiuid pressure with control valves for each fluid motor.

Figure 5 is a fragmentary, enlarged side elevational view of the second fluid motor taken partially in section along line 5-5 of Figure 1.

With particular reference to Figure 1, the actuator of the present invention, shown generally by the numeral 10, includes a cylinder 12 with end cap 14 and end fitting, structure or casing 16 threaded into engagement therewith by means of cooperating threads 15 and suitable seals 13 at opposite ends. The end cap 14 is pivotally attached as at 17 to fixed means. This portion of the actuator may be termed the first fluid motor and, as shown in Figure 4, has a piston 18 with a suitable packing 20 reciprocally disposed therein. The piston 18 divides the cylinder 12 into an extend chamber 26 and retract chamber 28. The piston 18 is connected to a piston rod end 30 which extends axially through an aperture in the end fitting or end structure 16 in a conventional manner. The piston rod end 30 is attached to an externally threaded actuating rod 32, which, in turn, may be connected to a load or aircraft surface (not shown) capable of multiple location positioning and preventing rotation of the rod to maintain alignment.

Figure 4 also shows a screw shaft 34 rotatably journalled in the end cap 14 by an assembly including a sleeve 36 rotatably supported in the end cap by bearings 38. The sleeve 36 is connected to the screw shaft at one end thereof by means of a pin 39 which extends through an aperture in the sleeve aligned with an aperture in the screw shaft 34 in a conventional manner. On the opposite end of the sleeve 36 there is disposed a pinion gear 40 which is fitted axially over the sleeve 36 together with a washer 41 to hold the inner raceway of the bearings 38 in assembled relationship thereto. A bushing 42 is disposed between the outer raceway of the bearings 38 and the cylinder 12 and end cap 14 in assembled relationship. The ,gear 40 is xed to the sleeve 36 by means of a nut 44 threadedvonto external threads 45 on the sleeve 36 l with a lock washer 46.

The cross-secional view shown in Figure 2 shows the gear 40 in mesh with a synchronizing `gear shaft 48 operable to Isynchronize the operation of the tirst fluid motor ot' theactuator 18 with like actuators as disclosed in my aforementioned Patent 2,657,539. This shaft 48 may be rotatably journalled by bearings 49 in` a synchronizing shaft housing 50 suitably attached as by brazing to the cylinder 12 of the actuator. The littings 22 are threaded into engagement with internal threads 51 at opposite ends of the housing 50 with a packing 52 providing a seal between each fitting and-the housing. As disclosed in my aforementioned patent, the fittings 22 serve as fluid supply ports as well as providing openings for mechanical interengagement with synchronizing means of like actuators.

The screw shaft 34, connected with the synchronizing gearing 40 and 48 as. just described, is rotatably connected to the piston 18 bymeans of an internally threaded nut 54. The nut 54 is rigidly connected to the piston 18 by means of a lock nut 55 threaded to the head portion of the piston 18 at the threaded portion 56. The piston 18 is provided with a metering oriice and passage 58 in accordance with piston cooling structure as disclosed in my copending application, S. N. 551,823, Geyer, tiled of even date herewith.

To provide multiple position actuatio-nin accordance withmy invention, a second fluid motor shown generally by the numeral 60 is disposed with the cylinder 12 and end titting, structure, or casing, 16, as shown in Figures l, 3, 4 and 5. This iiuid motor is shown in enlarged cross section in Figure and includes a cylinder 62 having a piston 64 with a suitable packing 65 reciprocally disposed therein. One end of the cylinder 62 is integral with the end casing 16 and is provided with a conduit 66 as shown in Figure 5. The other end of the cylinder 62 is open. The piston 64 and cylinder 62 form a chamber 67 in communication with conduit 66. A conduit 68 connects the chamber 67 to a drain port iitting 69. The conduit 66 connects with a pressure port fitting 70 shown on Figure 4. The port tittings 69 and 70, as connected with conduits just described, are drain and pressure ports, respectively, in relation to the chamber formed by the piston 64 with cylinder 62.

Figure 4 includes a schematic representation of a source of pressure provided by a pump 72 connected by a pipe 73 with a selector control valve 74 for the first fluid motor 10. The valve 74 comprises a cylinder 75 having ports 76 and 77 with a valve piston 78 reciprocal therein to selectively supply iiuid through pipe 79 connected with port fitting 22 (Figs. l and 2) and a pipe 80 connected with a port fitting 24 of the iirst fluid motor. A spring 82 biases the piston 78 in one direction in its cylinder 75 and suitable actuating means 83 may move the piston 78 in the opposite direction. A pipe 85 connects the pump 72 with a second selector control valve 86 comprising a cylinder 87 having a reciprocal valve member 88 disposed therein. The member 88 is biased by a spring 89 in one direction and movable through an actuating means 90 in-the opposite direction to selectively connect pipe 91 attached to fitting 70 of the second uid motor. The valve member 88'can connect pipe 92 attached to fitting 69 to drain to permit spring-biased retract movement of piston 64.

Fluid pressure actuation of the first iiuid motor as selectively controlled by the valve 74 just mentioned causes the actuating rod 32 to be moved axially to an extend or retract position. This actuating rod is capable of movement from a fully extended to a fully retracted position. As shown in Figure 1, however, the actuating rod is disposed with a stroke limiting means in accordance with the present invention. This provides multiple position actuation which is adjustable and removable to permit further extend actuation.

As shown in Figures 1 and 4, an internally threaded stroke adjusting nut 102 is threaded into engagement with the actuating rod 32 provided with external threads 100. A lock washer 103 is slipped over the actuating rod 32 engaging with a notched portion 104 in the stroke adjusting nut 102. A keyway 105 of actuating rod 32 is interlocked by means of the lock washer 103 to the notched portion of stroke adjusting nut 102. A jam nut 106, threaded onto the actuating rod 32, holds the stroke adjusting nut in a locked position relative to the keyway 105. Also threaded onto `the actuating rod 32 is a stroke limit adjusting nut 108 which may be axially spaced relative to the stroke adjusting nut 102 as desired. The stroke adjusting nut 102 is formed with axially extending and diametrically opposed slots, or grooves, 109, for receiving flange, tooth or hook portions 110 formed with a stroke limiting yoke, or annular member, 112. The stroke limiting yoke is slipped over the actuating rod 32 by means of a central aperture in the yoke so that the flange, tooth or hook portions 110 of the yoke are axially fitted into the grooves 109 formed on opposite sides of the stroke adjusting nut 102 as described. A jam nut 114 is threaded onto the actuating rod 32 and holds the yoke 112 against the stroke limit adjusting nut 108.

Figure l also shows the movable stroke limiting means for mechanically permitting selective engagement of the stroke limiting yoke 112 with the flange or hook portions 110 to engage a pair of stop members, locking jaws, or bifurcated members 116. The members 116 are pivotally disposed with respect to the end ycasing 16 by means of pins 118 journalled with anges 119 of casing 16. The members, or jaws, 116, include a web portion 120 which is engageable with the hook or tooth portions 110 of the stroke limit yoke 112 when the jaws 116 are in a position as Shown in Figure l. The jaws are normally urged into engaging position with these tooth portions by spring means including a spring 122 axially disposed on a jaw release member 124 connected through a pair of oppositely disposed gear teeth, or liange por-tion, 126, to the piston rod 94 attached to the piston 64 of the second uid motor 60. The spring 122, as can be clearly seen in Figure 5, is fitted between a flange portion 128 formed on the jaw release member and a spring retainer 130 attached by screws 132, as shown in Figure 1, to the end casing 16. The jaw release member 124 is formed with a reduced diameter portion 134 which is reciprocal through an aperture 135 formed in the spring retainer 130. The teeth 126 formed with the jaw release member 124 and connected with the piston rod -94 are movable linearly with respect to the axis of the spring 122 in accordance with tiuid pressure actuation of the piston 64 reciprocally disposed in cylinder 62 of the second uid motor 60. The teeth 126 engage a pair of piston actuating teeth 136 formed with the locking jaws 116 to be pivoted about the axis of the pins 118 together with any pivotal action of the locking jaws 116. The spring 122 keeps Ithe piston actuating teeth in the relationship shown in Figure l so that the web, portions 120 of the locking jaws 116 will engage toothed or flanged portions 110 of the yoke 112.

When the selector valve 86 is set to supply pressurized liuid through the pipe 91 and titting 70, the piston 64 moves axially to the right as shown in Figure 5 causing the teeth 126 to be moved to the right linearly as shown in Figure 1 so that the locking jaws 116 will be pivoted outwardly away from the actuating rod 32. Thus, if the first fiuid motor 10 has moved the actuating rod 32 to a position where the tiange portion 110 is in locking engagement with the web portion 120 of the locking jaws 116 in a tirst actuator position, pivoting the locking jaws 116 by means of fluid' pressure actuation of the second fluid motor 60 permits the actuating rod 32 to move to a further extended position.

Figures l, 3 and 4 show a rod shield 138 coaxially disposed with respect to the actuating rod 32 and suitably attached to the end structure 16. In Figures 1 and 4, the lshield 138 is partially sectioned. A cutout portion 140 1s provided on diametrically opposite sides of the rod shield 138 to permit the jaws 116 to be pivoted outwardly through the cutout portions or openings 140 permitting the web portions 120 to swing free of engagement with the tooth or flange portions 110 of the stroke limiting yoke 112. An aperture or cutout 141 in the top of the rod shield 138 provides space for the jaw release member 124 and spring retainer 130.

As shown in Figures 1 and 3, the jaws 116 have a beveled portion 142 formed on the inner edges of the webbed portions 120 so that, when the actuating rod 32 is moving in a retract direction, operative sliding engagement of the beveled portions 142 with the toothedor anged portions 110 of the stroke limiting yoke 112 is permitted in opposition to the biasing of spring 122 permitting full retraction of the actuating rod 32 under any conditions of operation. However, the actuating rod 32 cannot move in the extend direction beyond the stroke limiting means positioned as set by the adjusting nuts without uid pressure actuation of the second fluid motor to free the locking jaws 116 from the Iiange portions 110 of the stroke limiting yoke 112. Therefore, the stroke limiting means is entirely independent in its operation due to separate actuation of the second fluid motor 60 with respect to the rst uid motor 10.

Figures 1 and 3 show pairs of port ttings 69 and 70 disposed with the second uid motor so that similar second uid motors can be fluid pressure actuated simultaneously on like actuators having rst fluid motors synchronously interconnected by mechanical means as disclosed in my Patent 2,657,539.

While the embodiment of the present invention as herein disclosed constitutes a preferred form, it is to be understood that other forms might be adopted.

What is claimed is as follows:

1. A mechanism comprising in combination, a cylinder, a piston reciprocally disposed therein dividing said cylinder into an extend and retract chamber, an actuating rod connected with said piston, a pair of tooth members extending radially outwardly on said rod, an end casing attached to one end of said cylinder, a pair of stop members pivotally supported by said casing, means urging said stop members together to cooperate with said tooth members, and iluid pressure controlled means for spreading `apart the stop members to permit full actuator movement in one direction, said stop members limiting the stroke of said rod in one direction and permitting unrestricted movement under any condition in the opposite direction.

2. Stroke limiting means for a uid pressure actuator having a cylinder and a piston reciprocally disposed therein comprising, an actuating rod capable of being reciprocated in a full stroke by said actuator, a stroke limiting yoke adjustably disposed on said rod, a pair of stop jaws pivotally disposed on said actuator to cooperate with said stroke limiting yoke, means normally urging said jaws into engagement with said yoke, releasing means operably engaged with said jaws, and a uid motor for selectively lactuating said releasing means operably disposed on said actuator.

3. Stroke limiting means for a linear uid pressure actuator having a cylinder and a piston reciprocally disposed therein, comprising an actuating rod capable of being reciprocated by said actuator, an annular member adjustably disposed on said rod, a pair of axially-extend ing outwardly-protruding hook members connected with said annular member, a pair of bifurcated members pivotally disposed on said actuator, a web portion of said bifurcated members selectively movable into stroke limiting engagement with said hook members, means normally urging said web portion into engagement with said hook members, a toothed flange portion on each bifurcated member disposed to pivot about the axis therewith, an end structure disposed on said actuator,I and a reciprocating member movable in said structure and operatively engaging said toothed portions, said reciprocating member serving to eect selective release of engagement between said hook members and said web portions for unrestricted movement of said actuating rod.

4. An actuator assembly, comprising, in combination, a linear fluid pressure motor including a cylinder and a piston reciprocal therein, a non-rotatable actuating rod operably connected with said piston capable of moving from a fully retracted to a fully extended position, a pair of radially extending tooth portions on said rod, means for restraining said rod from moving between fully retracted and fully extended position including a pair of pivotally movable stop jaws having closed slots therein cooperable with said tooth portions, and means operably disposed on said assembly for spreading apart the stop jaws to permit full movement of said actuators.

5. An actuator assembly, comprising, :in combination, a linear uid pressure motor including a cylinder and a piston reciprocal therein, a non-rotatable actuating rod operably connected with said piston capable of moving from a fully retracted to a fully extended position, a stroke limiting abutment means on diametrically opposite sides of said rod, means for retraining said rod from moving between fully retracted Iand fully extended position including a pair of pivotally movable stop members located at diametrically opposite sides of said rod and engageable with said abutment means, and means operably disposed with said assembly for pivoting said diametrically opposite stop members to a position wherein said stop members are free of engaging said diametrically opposite abutment means.

References Cited in the tile of this patent UNITED STATES PATENTS 1,469,689 Prius Oct. 2, 1923 1,965,751 Rush July 10, 1934 2,056,006 Hodgkins Sept. 29, 1936 2,118,890 Maes May 31, 1938 2,542,463 Beard` Feb. 20, 1951 2,657,539 Geyer Nov. 3, 1953 2,688,232 Geyer Sept. 7, 1954 

